Sixty-eight year old healthy man has had
multiple implants. He readily accepted immediate implant when the
tooth #5 had subgingival fracture of the lingual cusp (Fig.1).
A 5x20 mm Tatum screw implant was placed immediately after atraumatic extraction
and bone expansion (Fig.2
I). Implant rough surface was exposed buccally and lingually when the
implant was placed equigingivally proximally. Two buccal accessory
incisions were made. The flap was raised with scoring the periosteum
underneath, advanced downward (as shown in
Fig.3 arrow) and sutured to
the lingual papilla. The buccal aspect of the implant is covered, whereas
the lingual rough surface remains partially exposed (Fig.4
arrow), assuming that the palatal mucoperiosteum is tough to advance even with
release incisions.

Fig.3 and 4 are taken 1 week postop, whereas
Fig.5 and
6 (mirror view) are taken 2
weeks postop.

Fig.7-9 are taken 3.5 months postop. Buccal gingiva appears to have
elevated (Fig.8 arrow, as
compared to Fig.5 B). The rough surface seems to have been partially
covered by lingual gingiva (Fig.9
arrowheads, as compared to Fig.6).

My questions are as follows.

It appears that exposed rough surface causes no harm. Can the lingual
margin be placed on the smooth portion of the implant when prepared for crown?
Or does the rough surface need to be covered by crown?

Hello Dr. Wei, You may recall, I said I always prefer to
place an implant at the time of the extraction . In order to
prevent the exposure of threads you must cover any exposed
threads at the time with a graft material and then have
primary closure by movement of crestal soft tissue. I
preferred using Biogran as the graft material. Now that
healing has taken place and threads are exposed, I would
prefer to remove the exposed threads and prep the implant to
the bone crest on my abutement. If the threads are left
exposed the bacteria will have a path (along the thread)
into the bone. Dr Borgner11/13/2011

Dear Dr. Borgner: Thank you very much for the
reply, which is very helpful. In fact, after studying
Tatum implant design, I found out that only the rough
surface of screw type implant is exposed lingually (~1
mm), not threads. Does crown still need to cover the
rough surface? The rough surface can also trap
bacteria?

Dr Wei, Rough surface exposure is not as important, I
would polish the exposed surface with a polishing wheel when
prepped. It looks like the implant has healed well. Dr
Borgner 11/16/2011